It is known to provide a motor vehicle with an engine stop-start system for automatically stopping and starting the engine whenever it is determined from driver actions that there is an opportunity to do so in order to reduce fuel consumption and reduce emissions from the engine.
However, the inventors herein have recognized potential issues with such engine stop-start systems. As one example, if the time taken to stop and then restart the engine is excessive, the delay may lead to dissatisfaction in a user of the motor vehicle. In addition, such an excessive delay, may also result in actual use problems if the driver wrongly concludes that the system has failed to restart the engine in response to their actions.
In one example, the issues described above may be addressed by a method for . . . controlling a fuel supply system of an engine of a motor vehicle wherein the method comprises, during a shutdown of the engine, operating an engine driven variable output high pressure fuel pump at a high demand level and storing fuel from the high pressure fuel pump in a fuel accumulator and, during a subsequent engine start-up, operating the high pressure fuel pump at a low demand level and supplying fuel from the accumulator to the engine.
In another example, a fuel supply system of an engine of a motor vehicle comprising an engine driven variable output high pressure fuel pump, a fuel accumulator to store fuel at high pressure, a valve means to control the flow of high pressure fuel within the system and an electronic controller to control the operation of the high pressure fuel pump and the valve means, wherein the controller is operable during a shutdown of the engine, to operate the high pressure fuel pump at a high demand level and control the valve means to store fuel from the high pressure fuel pump in the fuel accumulator and is operable, during a subsequent engine start-up, to operate the high pressure fuel pump at a low demand level and operate the valve means so that fuel from the fuel accumulator is supplied to the engine.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.